420c Hydraulic pump

[astro57]

Hi just finished getting my dozer running, sleeves in the cylinders and a rebuild. left final drive bearing replacement. now my pump has a cracked housing, this doesn't seem uncommon. I am looking for ideas for a substitute pump rather than buying another housing only to have it crack.
Thanks

[GaCatskinner]

If it is run off the motor crankshaft then any pump with the proper GPM could be made to work. You would just need to figure out which one would be the easiest to mount. Use a Lovejoy coupling to connect to engine. Best places to look would be Bailey's hydraulics or Northern Tool.

[Lavoy]

Cam or crank pump? If crank pump, there are almost no parts new or used available. If cam pump, there is no other pump that will fit in there, so no choice.
Lavoy

[astro57]

It is currently a cam driven pump but I am more interested in converting something to be driven off the crank, probably have turn something to bolt to the crank pulley to drive the pump, physically not a lot of space up front though for a pump, good thing that it likely wouldn't require much of a pump to drive one cylinder.

[Lavoy]

Not really sure why you want to go away from the factory pump, there is no gain to a crank pump, and likely more hassle. You will need a whole new front casting unless you butcher the heck out of yours. You will need a really small pump about 9GPM, and will have to fab all new lines and such. I can't really see how this is better or cheaper than what it came with.
Lavoy

[astro57]

Not really sure why you want to go away from the factory pump, there is no gain to a crank pump, and likely more hassle. You will need a whole new front casting unless you butcher the heck out of yours. You will need a really small pump about 9GPM, and will have to fab all new lines and such. I can't really see how this is better or cheaper than what it came with.
Lavoy

My concern was mostly about cracking another housing, my search for a pump yielded more than one cracked one. The original is definitely the simplest route. Is the pump cracking a common issue? How much for a good housing?

Thanks for the help

[Stan Disbrow]

Hi,

Well, Lavoy has been around a lot more of these machines than I have. That said, I have been around a lot of them and not seen where these original pumps crack unless they wound up with water in them and winter came along...

Stan

[Lavoy]

Frozen or dead headed is the only two reasons I can think of. I have seen it, but I have had a couple hundred of these crawlers, so I probably should have seen some.
There is nothing wrong with the original pumps, rebuild yours, put in a used center section and you should be fine. I will have to check and see if I have a loose center section. Shoot me an e-mail when you get a chance, and I will do some digging.
Lavoy

[notmeu]

My concern was mostly about cracking another housing, my search for a pump yielded more than one cracked one. The original is definitely the simplest route. Is the pump cracking a common issue? How much for a good housing?

Thanks for the help[/quote]

Is it possible that you have the relief valve set above 1000 psi? And it cracked the housing?

[astro57]

Is it possible that you have the relief valve set above 1000 psi? And it cracked the housing?[/quote]

Couldn't answer that, This thing came with the house I bought, and was not in running condition. While doing the engine I noticed the cracked pump. One problem seems to expose another. My brother told me two things:

1: If you own a dozer you will always have something to work on
2: You will never realize how little you needed a dozer until you own one.